and NEVER use the Arduino type “word” as that is defined to be “unsigned short” which is 16 bits on AVR and 32 bits on ARM and pic32. I'm using an unsigned long … char vs signed char vs unsigned char. If you don’t, the result of the subtraction will become negative if given the right input. So the only way to allow libraries to be portable between ESP32 Arduino core and other cores is to use unsigned long for the return value. Hello, I am trying to modify a library at the moment. So it COMMON for char to be 8bits, int to be either 16 or 32, and long to 32. Which means that your fancy magic number on the right hand side is going to be truncated to about 6 decimal digits of precision anyway. In the Arduino int type (which is signed), if the high bit is a "1", the number is interpreted as a negative number, and the other 15 bits are interpreted with (2’s complement math). // frequency is a double int32_t freq = frequency * 4294967296 / 180.0e6; That calculation is going to be done using floating point arithmetic. It's 64bits on ARM, and only 32 (the same as "float") on AVR. Modern programmers should use the standardized explicit-size types instead: uin8_t, int16_t, uint32_t, etc. Am I wrong? I would discourage using the “cutsie” Arduino types like byte. uint16_t and uint32_t (the same as unsigned long on However in C++ int and long are different types, even if they are of the same size. The “word” type is a total fail. But what are ranges of all these types? Some architecture use 64 bits for long type..LP64 convention use 64 bits for long type. The difference between unsigned ints and (signed) ints, lies in the way the highest bit, sometimes referred to as the "sign" bit, is interpreted. It turns out that they are equal respectively to: unsigned char, unsigned short, unsigned int and unsigned long long. Unlike standard longs, unsigned longs will not store negative numbers, making their range from 0 to 4,294,967,295 (2^32 - 1). You may use long type also for inet_addr() function since most of the architecture use 32 bits(4 bytes) for long type but it is not always applicable . As @erenfro correctly noted, this isn't a bit width issue, as both int and long are 32 bit on Xtensa. The library uses: uint8_t and uint16_t Until now I am only used of using the int and unsigned int (data types as described in the arduino … The exact same bits, just considered as a 2's-complement integer instead of as an unsigned integer. That's a good question. Printing a uint32_t value with "%u" is non-portable. It could plausibly be either unsigned int or unsigned long int. Because it could be really helpul! I don't think simply casting it to long will do the trick. Example Unsigned Long velocity = 101006 ;// declaration of variable with type Unsigned Long and initialize it with 101006 Unsigned long variables are extended size variables for number storage and store 32 bits (4 bytes). Or perhaps there's a better way. On Arduino Uno (and equivalent) you have to explicitly cast the calculation when dealing with uint8_t for this to work. int infrared1 = A0; int infrared2 = A1; #define button 9 int color,number,number1,number2; unsigned long firstMillis1; unsigned long firstMillis2; unsigned long secondMillis1; "long" has almost always been 32bits. But the size of uint32_t is always 32 bits independent of convention the compiler is following.. 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arduino uint32_t vs unsigned long 2021